We thank the authors for their valuable contributions to this volume and George Telecki order 100 mg zithromax, the Executive Editor and Shirley Thomas discount 500mg zithromax amex, Senior Associate Managing Editor of John Wiley & Sons, Inc. Metin Akay This work was partially supported by a USA NSF grant (IEEE EMBS Work- shop on Virtual Reality in Medicine, BES ± 9725881) made to Professor Metin Akay. INFORMATION TECHNOLOGIES IN MEDICINE Information Technologies in Medicine, Volume I: Medical Simulation and Education. ISBNs: 0-471-38863-7 (Paper); 0-471-21669-0 (Electronic) PART I ARTIFICIAL ENVIRONM ENT AND M EDICAL STIM ULATOR/EDUCATION Information Technologies in Medicine, Volume I: Medical Simulation and Education. ISBNs: 0-471-38863-7 (Paper); 0-471-21669-0 (Electronic) CHAPTER 1 Virtual Reality in edicine and Biology RICHARD A. Traditionally, these visualizations either have been direct, via vivisection and postmortem examination, or have required extensive mental reconstruction, as in the microscopic examination of serial histologic sec- tions. The revolutionary capabilities of new three-dimensional (3-D) and four- dimensional (4-D) imaging modalities and the new 3-D scanning microscope technologies underscore the vital importance of spatial visualization to these sciences. Computer reconstruction and rendering of multidimensional medical and histologic image data obviate the taxing need for mental reconstruction and provide a powerful new visualization tool for biologists and physicians. Voxel-based computer visualization has a number of important uses in basic research, clinical diagnosis, and treatment or surgery planning; but it is limited by relatively long rendering times and minimal possibilities for image object manipulation. The use of virtual reality (VR) technology opens new realms in the teaching and practice of medicine and biology by allowing the visualizations to be manipulated with intuitive immediacy similar to that of real objects; by allow- ing the viewer to enter the visualizations, taking any viewpoint; by allowing the objects to be dynamic, either in response to viewer actions or to illustrate nor- mal or abnormal motion; and by engaging other senses, such as touch and hearing (or even smell) to enrich the visualization. Biologic applications extend across a range of scale from investigating the structure of individual cells through the organization of cells in a tissue to the representation of organs and organ systems, including functional attributes such as electrophysiologic signal distribution on the surface of an organ. Medical applications include basic anatomy instruction, surgical simulation for instruction, visualization for diagnosis, and surgical simulation for treatment planning and rehearsal. Although the greatest potential for revolutionary innovation in the teaching and practice of medicine and biology lies in dynamic, fully immersive, multi- sensory fusion of real and virtual information data streams, this technology is still under development and not yet generally available to the medical re- searcher. There are, however, a great many practical applications that require di¨erent levels of interactivity and immersion, that can be delivered now, and that will have an immediate e¨ect on medicine and biology. In developing these applications, both hardware and software infrastructure must be adaptable to many di¨erent applications operating at di¨erent levels of complexity. Inter- faces to shared resources must be designed ¯exibly from the outset and crea- tively reused to extend the life of each technology and to realize satisfactory return on the investment. Crucial to all these applications is the facile transformation between an im- age space organized as a rectilinear N-dimensional grid of multivalued voxels and a model space organized as surfaces approximated by multiple planar tiles. The most complex and challenging applications, those that show the greatest promise of signi®cantly changing the practice of medical research or treatment, require an intimate and immediate union of image and model with real-world, real-time data. It may well be that the ulti- mate value of VR in medicine will derive more from the sensory enhancement of real experience than from the simulation of normally sensed reality. A successful virtual envi- ronment is one that engages the user, encouraging a willing suspension of dis- belief and evoking a feeling of presence and the illusion of reality. Although arcade graphics and helmeted, gloved, and cable-laden users form the popular view of VR, it should not be de®ned by the tools it uses but rather by the functionality it provides. VR provides the opportunity to create synthetic real- ities for which there are no real antecedents and brings an intimacy to the data by separating the user from traditional computer interfaces and real-world constraints, allowing the user to interact with the data in a natural fashion. To produce a feeling of immersion or presence (a feeling of being physically present within the synthetic environment) the simulation must be capable of real-time interactivity; technically, a minimum visual update rate of 30 frames per second and a maximum total computational lag time of 100 ms are required (1, 2). Together with Performer (3), these systems allow us to design visualization software that uses coarse-grained multiprocessing, reduces computational lag time, and improves the visual update rate. These systems were chosen primarily for their graphics performance and our familiarity with other Silicon Graphics hardware. We support ``®sh-tank' immersion through the use of Crystal Eyes stereo glasses and fully immersive displays via Cybereye head-mounted displays (HMDs). By displaying interlaced stereo pairs directly on the computer moni- tor, the stereo glasses provide an inexpensive high-resolution stereo display that can be easily shared by multiple users. Unfortunately, there is a noticeable lack of presence and little separation from the traditional computer interface with this type of display. The HMD provides more intimacy with the data and im- proves the sense of presence. We chose the Cybereye HMD for our initial work 6 VIRTUAL REALITY IN MEDICINE AND BIOLOGY with fully immersive environments on a cost/performance basis. Although it has served adequately for the initial explorations, its lack of resolution and re- stricted ®eld of view limit its usefulness in serious applications. We are currently evaluating other HMDs and display systems to improve display quality, in- cluding the Immersive Workbench (FakeSpace) and the Proview HMD (Kaiser Electro-Optics). Our primary three space tracking systems are electromagnetic 6 degree of freedom (DOF) systems. Initially, three space tracking was done using Polhe- mus systems, but we are now using an Ascension MotionStar system to reduce the noise generated by computer monitors and ®xed concentrations of ferrous material. In addition to electomagnetic tracking, we support ultrasonic and mechanical tracking systems. This allows for 3 degrees of force feedback, which we ®nd adequate for simulating most puncture, cut- ting, and pulling operations. To accommodate the various levels of com- plexity while maintaining a suitable degree of interactivity, our simulation in- frastructure is based on a series of independent agents spread over a local area network (LAN). Presently, the infrastructure consists of an avatar agent run- ning on one of the primary VR workstations and a series of device daemons running on other workstations on the network.

She parented her mother and sister to make up for the guilt she felt over having taken away the husband and father zithromax 100 mg for sale. All the difﬁculties that this client exhibited were dealt with outside of herself buy 250 mg zithromax free shipping. Thus, when the stress, humiliation, and shame mounted, she would act out (ultimately on the two people she was parenting—her sister and mother), purge herself of her shame through aggression, and then become the symbol of perfection. She formed a pestle and mortar (penis and va- gina), exploding crowns on the trees, a bodiless person, and on and on. In this client’s case her inductive reasoning surrounded the belief that if bad things happen it is because you are bad. Overall, shame and humilia- tion are prominent as the child begins to struggle with complex problems. Thus, ﬁxated as she was at the intuitive stage of development, rationaliz- ing was her main verbal defense, which made traditional therapy ineffec- tive. Yet with art therapy the thoughts and feelings she had hidden from consciousness were allowed symbolic expression, and the defense mecha- nisms of conversion and reaction formation were then articulated. In the end it is the typical and predictable sequences of behavior that I utilize to guide my use of the art, choice of media, and the ensuing direc- tives. For without a cornerstone to guide us we would be hard pressed to in- terpret the artwork in any manner other than a haphazard one. The art of art therapy is less about how pleasingly the drawing is ren- dered and more about the elements that are either drawn or disregarded. It has been suggested in psychological as well as art literature that individuals project their personality into their drawings. Lowenfeld and Brittain (1982) state, "The child draws only what is actively in his mind. Therefore the drawing gives us an excellent record of the things that are of importance to the child during the drawing process. In the same manner any person, regardless of age, whether versed or not in the art of drawing, utilizes an unconscious process that allows for more freedom than verbalization affords. Other drawings that this client pro- duced showed he was capable of drawing people, places, and environments. Unfortunately, as he emotionally decompensated, his drawings increas- ingly worsened until they took on an infantile quality (which is often char- acteristic of coartated schizophrenics). This is an important distinction to make, as interpre- tation revolves around not only the completed art project but also the cli- ent’s verbal statement regarding the rendering. As Lowenfeld and Brittain (1982) aptly state, To examine the picture without understanding what the child’s intention was, to make assumptions about personality from one example of artwork, or to assess competence in art on the basis of what is included or omitted from the product, does both the product and the child an injustice. This includes the client’s social and familial history (recent and remote), cultural identity, medical history (including medications), chronological age, presenting problem, substance abuse his- tory, developmental history, mental status, and of course his or her verbal- ization about the completed project. All of these elements are necessary for a correct interpretation of the product and an accurate understanding of the client’s mental health. DiLeo (1973) states, "valid appraisal of a child’s drawing is not possible without taking into account the age and developmental level.... Thesig- niﬁcance of omission and exaggeration depends upon the level at which the child is functioning. Note the oversized head and the beginning of attentiveness to environmental detail (e. He then drew the ﬁgure’s left arm, worked his way down to the left leg, and in drawing the right leg connected the line to the hand area of the right arm. At this point he looked at the drawing quizzically, seeming to understand that something was wrong but not what or how to ﬁx the problem. At this point I gave him a second piece of paper and instructed him to begin over. This could be due to the fact that children rely on primary processing un- til they move into a logical mode of reasoning at roughly the age of seven. Equally, schizophrenics operate on primary processing, which relies heav- ily on primitive, id-related experiences and also runs counter to a logical mode of reasoning. Images showing organicity will be reviewed in detail in Chapter 3; how- ever, I have chosen to illustrate one that clearly deﬁnes a general retarda- tion in development. A psychiatric evaluation dated one year prior to my assessment stated that the patient had been given drug injec- tions, against his will, which resulted in toxic psychosis. According to Piaget’s theory of child development, during the precon- ceptual phase the child is able to hold mental representations of objects in his or her head. Howard Gardner (1980) says this about tadpole ﬁgures: "While they tend to have two protuberances at the bottom, which are usually seen as legs, and may (less frequently) have two extensions on the side, which are per- haps arms, they consist of but a single central circle" (p. From the tadpole person playing golf in the foreground to the house, lo- cated on the viewer’s left, and the tree on the right, each detail points to- ward an internal model rather than any degree of realism. The house has a garage in the lower right square with a car parked in it, yet the car is drawn from a worm’s-eye view and is more a symbol than a representation. The tree has a baseline that wraps around the trunk, while the crown of the tree is drawn as a black ball; the branches extend from the trunk into the air in- stead of into the crown itself. This distorted and disorganized vision is cer- tainly a trademark of schizophrenia with concomitant pervasive develop- mental delays, yet in a child’s renderings it could designate a normal phase of development. I cannot stress enough the importance of understanding the develop- mental stages when interpreting the artwork, yet when utilizing art one must also take into account the chosen medium. The use of media can en- hance a client’s functioning, frustrate the client, or offer an inaccurate pic- ture of his or her personality and any developmental delays that may exist.